We expected them to be available at launch, so we asked Fractal and they assured us they are heading to retailers and should show up soon. When it pops up somewhere it should show up in our listings pretty quickly.

I live in a very dusty city. I am not crazy about having the CPU radiator on top. Would it be possible to mount the CPU radiator on the bottom and if so, would it require a different model radiator (from a different manufacturer?) and then would it be possible to have the graphics card radiator exhaust somewhere else or is there room to have the graphics card exhaust out the bottom simultaneously?

The bottom of the case can technically accommodate a 240mm radiator for the CPU (down where we put the 120mm radiator for the GPU). Though you'll need to keep an eye on your PSU's length to avoid cables not fitting against the end of the radiator. You'll also need to make sure you're tubing can reach from the CPU to the bottom. I'm not sure off hand if Fractal's Celsius S24 (or any) 240mm AIO radiators could reach that far without a bit of testing. It might take a custom loop to make that work.

The Define R6 is being marketed towards a different crowd, of which you don't seem to fall in to. For you, the Define S has all you need. For me, the R6 has many features I find desirable. Its all personal preference really.

The fan hub is PWM, yes. I prefer cases with an abundance of HDD bays because I'm too cheap to shell out the cash for a proper NAS bay (included HDD bays vs. $500 4 bay NAS). I also still take advantage of optical media (not as much as I used to, but usually once or twice every few days).

From the specs they provided, it looks like it can control 3 PWM fans (plus 6 case fans) based on a single PWM motherboard header. So yeah, sounds like for PWM control past the first 3, you'll need additional headers.